18 



KNOWLEDGE 



[Januaby 2, 1899. 



.MjThe maximum which was computed for June 17th seems 

 to have occurred July 6fch, or twenty days late. The 

 movements of the star were very perplexing, but not more 

 so than those of 



1898. 



May 17 



„ 18 



„ 23 



., 28 



„ 29 



„ 30 



June 5 



., 6 (very red) 



„ 10 



„ 12 



„ 14 



„ 17 



„ 22 



„ 23 



The maximum was predicted for .June 14th ; apparently 

 it may be placed on July 4th, or twenty days late. I have 

 hesitated in showing a discrepancy of over a magnitude in 

 this star on June 12th until, looking up its record, I found 

 a similar discrepancy in Mr. Henry M. Parkhurst's record 

 for 1897. SeeAstronowical Journal, No. 421, p. 99, where 

 he says, " The discrepancy of a magnitude, 1897, April 15, 

 is neither a typographical or clerical error." In this case, 

 as in that of the fluctuations of Mira three or four years 

 ago, finding myself in the best company, the figures are 

 submitted to the common arbitrator. 



There were many other observations of both stars made, 

 but only definite changes are given. 



Ceti (Mira) reached a brilliant maximum, 1898, 

 October 3rd, at 2-2 magnitude. 



The star rose this season at later hours than I can keep, 

 but I lost no available opportunity for an observation. 

 My dates and estimates are as follows : — 



Following the terms of the second catalogue the maxi- 

 mum was due July 27th ; it occurred October 3rd, about 

 sixty-eight days late. 



The seeming fluctuations were of a minor character, and 

 may reasonably be charged to errors of observations ; 

 they may occur yet. Mira does not reach the meridian 

 till near midnight, so there will be an opportunity to 

 follow it down. 



CojiPAEisoN Stabs ttsed. 



THE SUNSPOT PERIOD. 

 To the Editors of Knowledge. 



Sirs, — In his very interesting article on " The Great 

 Sunspot and the Aurora," which appeared in Knowledge, 

 for October, Mr. Maunder intimates that the last spot 

 maximum occurred in 1893, which I do not for one 

 moment doubt. He then suggests that the approaching 

 minimum will be reached about two years hence, or, in 

 something less than seven years after the maximum. He 

 is fully competent to make such a statement. Once more. 

 In the Journal of the British Asimnomical Association, 

 ^'ol. I., No. 2, page 91, he is quoted as stating that the 

 last sunspot minimum fell in 1889. Again, this accords 

 with my own humble experience. But what puzzles me 

 is to know how the " rule " mentioned in the first para- 

 graph of the October Knowledge article is established. 

 Are we to understand that the interval between minimum 

 and maximum is generally between four and five years ; 

 and that the period separating maximum from minimum 

 usually approximates to seven years ? Or, are we simply 

 to take it that the passage from minimum to maximum, as 

 a rule, requires less time than does the opposite phase of 

 the phenomenon ? William Godden. 



38, Burrard Road, West Hampstead, N.W., 

 19th November, 1898. 



TREE STRUCK BY LIGHTNINa. 

 To the Editors of Knowledge. 



Sirs, — Perhaps some of your readers will kindly tell me 

 what actually takes place when a tree is struck by light- 

 ning ■? I have in my mind a big ash tree which this 

 summer was completely riven in two and split into match 

 wood, and a large arm torn entirely off; what is the 

 force which has been exerted ? Is it that all the sap and 

 liquid has been instantaneously turned into steam by the 

 enormous heat produced, causing the wood to swell and 

 burst ; or what is the force exerted ? 



October 16th, 1898. A. C. 



Eebata. — In the Deiember, 1898, number of KNOyfLEBGE, on 

 page 277, column 2. line 5 from bottom, for " crescends," read 

 "crescendo"; line 3 from bottom, for " L'laricinists," read " clavi- 

 cinists" ; page 278, line 1, for " Hamsau," read " Rameau " ; line 6, 

 for "crescends," read " crescendo." 



THE OVIPOSITOR OF A BEETLE (BAPTOLINUS 



ALTERNANS) AND THE TEETH OF 



THE DUNG FLY. 



By Walter WEscui;. 



BAFTOLINUS altcmans is a small beetle, about 

 three-eighths of an inch in length. Mr. Water- 

 house tells me it is rather rare, but he has found 

 it in decaying wood, and this remarkable ovipositor, 

 consisting of a number of curiously formed hooks, 

 seems well adapted for scratching out holes in such a 

 substance. The specimen figured was found in a garden 



